Add example file
This commit is contained in:
parent
5cd1718a3b
commit
0d8efd2f05
1 changed files with 258 additions and 0 deletions
258
src/videostab.cpp
Normal file
258
src/videostab.cpp
Normal file
|
@ -0,0 +1,258 @@
|
|||
#include <opencv2/opencv.hpp>
|
||||
#include <iostream>
|
||||
#include <cassert>
|
||||
#include <cmath>
|
||||
#include <fstream>
|
||||
|
||||
using namespace std;
|
||||
using namespace cv;
|
||||
|
||||
// This video stablisation smooths the global trajectory using a sliding average window
|
||||
|
||||
const int SMOOTHING_RADIUS = 30; // In frames. The larger the more stable the video, but less reactive to sudden panning
|
||||
const int HORIZONTAL_BORDER_CROP = 20; // In pixels. Crops the border to reduce the black borders from stabilisation being too noticeable.
|
||||
|
||||
// 1. Get previous to current frame transformation (dx, dy, da) for all frames
|
||||
// 2. Accumulate the transformations to get the image trajectory
|
||||
// 3. Smooth out the trajectory using an averaging window
|
||||
// 4. Generate new set of previous to current transform, such that the trajectory ends up being the same as the smoothed trajectory
|
||||
// 5. Apply the new transformation to the video
|
||||
|
||||
struct TransformParam
|
||||
{
|
||||
TransformParam() {}
|
||||
TransformParam(double _dx, double _dy, double _da) {
|
||||
dx = _dx;
|
||||
dy = _dy;
|
||||
da = _da;
|
||||
}
|
||||
|
||||
double dx;
|
||||
double dy;
|
||||
double da; // angle
|
||||
};
|
||||
|
||||
struct Trajectory
|
||||
{
|
||||
Trajectory() {}
|
||||
Trajectory(double _x, double _y, double _a) {
|
||||
x = _x;
|
||||
y = _y;
|
||||
a = _a;
|
||||
}
|
||||
|
||||
double x;
|
||||
double y;
|
||||
double a; // angle
|
||||
};
|
||||
|
||||
int main(int argc, char **argv)
|
||||
{
|
||||
if(argc < 2) {
|
||||
cout << "./VideoStab [video.avi]" << endl;
|
||||
return 0;
|
||||
}
|
||||
|
||||
// For further analysis
|
||||
ofstream out_transform("prev_to_cur_transformation.txt");
|
||||
ofstream out_trajectory("trajectory.txt");
|
||||
ofstream out_smoothed_trajectory("smoothed_trajectory.txt");
|
||||
ofstream out_new_transform("new_prev_to_cur_transformation.txt");
|
||||
|
||||
VideoCapture cap(argv[1]);
|
||||
assert(cap.isOpened());
|
||||
|
||||
Mat cur, cur_grey;
|
||||
Mat prev, prev_grey;
|
||||
|
||||
cap >> prev;
|
||||
cvtColor(prev, prev_grey, COLOR_BGR2GRAY);
|
||||
|
||||
// Step 1 - Get previous to current frame transformation (dx, dy, da) for all frames
|
||||
vector <TransformParam> prev_to_cur_transform; // previous to current
|
||||
|
||||
int k=1;
|
||||
int max_frames = cap.get(CV_CAP_PROP_FRAME_COUNT);
|
||||
Mat last_T;
|
||||
|
||||
while(true) {
|
||||
cap >> cur;
|
||||
|
||||
if(cur.data == NULL) {
|
||||
break;
|
||||
}
|
||||
|
||||
cvtColor(cur, cur_grey, COLOR_BGR2GRAY);
|
||||
|
||||
// vector from prev to cur
|
||||
vector <Point2f> prev_corner, cur_corner;
|
||||
vector <Point2f> prev_corner2, cur_corner2;
|
||||
vector <uchar> status;
|
||||
vector <float> err;
|
||||
|
||||
goodFeaturesToTrack(prev_grey, prev_corner, 200, 0.01, 30);
|
||||
calcOpticalFlowPyrLK(prev_grey, cur_grey, prev_corner, cur_corner, status, err);
|
||||
|
||||
// weed out bad matches
|
||||
for(size_t i=0; i < status.size(); i++) {
|
||||
if(status[i]) {
|
||||
prev_corner2.push_back(prev_corner[i]);
|
||||
cur_corner2.push_back(cur_corner[i]);
|
||||
}
|
||||
}
|
||||
|
||||
// translation + rotation only
|
||||
Mat T = estimateRigidTransform(prev_corner2, cur_corner2, false); // false = rigid transform, no scaling/shearing
|
||||
|
||||
// in rare cases no transform is found. We'll just use the last known good transform.
|
||||
if(T.data == NULL) {
|
||||
last_T.copyTo(T);
|
||||
}
|
||||
|
||||
T.copyTo(last_T);
|
||||
|
||||
// decompose T
|
||||
double dx = T.at<double>(0,2);
|
||||
double dy = T.at<double>(1,2);
|
||||
double da = atan2(T.at<double>(1,0), T.at<double>(0,0));
|
||||
|
||||
prev_to_cur_transform.push_back(TransformParam(dx, dy, da));
|
||||
|
||||
out_transform << k << " " << dx << " " << dy << " " << da << endl;
|
||||
|
||||
cur.copyTo(prev);
|
||||
cur_grey.copyTo(prev_grey);
|
||||
|
||||
cout << "Frame: " << k << "/" << max_frames << " - good optical flow: " << prev_corner2.size() << endl;
|
||||
k++;
|
||||
}
|
||||
|
||||
// Step 2 - Accumulate the transformations to get the image trajectory
|
||||
|
||||
// Accumulated frame to frame transform
|
||||
double a = 0;
|
||||
double x = 0;
|
||||
double y = 0;
|
||||
|
||||
vector <Trajectory> trajectory; // trajectory at all frames
|
||||
|
||||
for(size_t i=0; i < prev_to_cur_transform.size(); i++) {
|
||||
x += prev_to_cur_transform[i].dx;
|
||||
y += prev_to_cur_transform[i].dy;
|
||||
a += prev_to_cur_transform[i].da;
|
||||
|
||||
trajectory.push_back(Trajectory(x,y,a));
|
||||
|
||||
out_trajectory << (i+1) << " " << x << " " << y << " " << a << endl;
|
||||
}
|
||||
|
||||
// Step 3 - Smooth out the trajectory using an averaging window
|
||||
vector <Trajectory> smoothed_trajectory; // trajectory at all frames
|
||||
|
||||
for(size_t i=0; i < trajectory.size(); i++) {
|
||||
double sum_x = 0;
|
||||
double sum_y = 0;
|
||||
double sum_a = 0;
|
||||
int count = 0;
|
||||
|
||||
for(int j=-SMOOTHING_RADIUS; j <= SMOOTHING_RADIUS; j++) {
|
||||
if(i+j >= 0 && i+j < trajectory.size()) {
|
||||
sum_x += trajectory[i+j].x;
|
||||
sum_y += trajectory[i+j].y;
|
||||
sum_a += trajectory[i+j].a;
|
||||
|
||||
count++;
|
||||
}
|
||||
}
|
||||
|
||||
double avg_a = sum_a / count;
|
||||
double avg_x = sum_x / count;
|
||||
double avg_y = sum_y / count;
|
||||
|
||||
smoothed_trajectory.push_back(Trajectory(avg_x, avg_y, avg_a));
|
||||
|
||||
out_smoothed_trajectory << (i+1) << " " << avg_x << " " << avg_y << " " << avg_a << endl;
|
||||
}
|
||||
|
||||
// Step 4 - Generate new set of previous to current transform, such that the trajectory ends up being the same as the smoothed trajectory
|
||||
vector <TransformParam> new_prev_to_cur_transform;
|
||||
|
||||
// Accumulated frame to frame transform
|
||||
a = 0;
|
||||
x = 0;
|
||||
y = 0;
|
||||
|
||||
for(size_t i=0; i < prev_to_cur_transform.size(); i++) {
|
||||
x += prev_to_cur_transform[i].dx;
|
||||
y += prev_to_cur_transform[i].dy;
|
||||
a += prev_to_cur_transform[i].da;
|
||||
|
||||
// target - current
|
||||
double diff_x = smoothed_trajectory[i].x - x;
|
||||
double diff_y = smoothed_trajectory[i].y - y;
|
||||
double diff_a = smoothed_trajectory[i].a - a;
|
||||
|
||||
double dx = prev_to_cur_transform[i].dx + diff_x;
|
||||
double dy = prev_to_cur_transform[i].dy + diff_y;
|
||||
double da = prev_to_cur_transform[i].da + diff_a;
|
||||
|
||||
new_prev_to_cur_transform.push_back(TransformParam(dx, dy, da));
|
||||
|
||||
out_new_transform << (i+1) << " " << dx << " " << dy << " " << da << endl;
|
||||
}
|
||||
|
||||
// Step 5 - Apply the new transformation to the video
|
||||
cap.set(CV_CAP_PROP_POS_FRAMES, 0);
|
||||
Mat T(2,3,CV_64F);
|
||||
|
||||
int vert_border = HORIZONTAL_BORDER_CROP * prev.rows / prev.cols; // get the aspect ratio correct
|
||||
|
||||
k=0;
|
||||
while(k < max_frames-1) { // don't process the very last frame, no valid transform
|
||||
cap >> cur;
|
||||
|
||||
if(cur.data == NULL) {
|
||||
break;
|
||||
}
|
||||
|
||||
T.at<double>(0,0) = cos(new_prev_to_cur_transform[k].da);
|
||||
T.at<double>(0,1) = -sin(new_prev_to_cur_transform[k].da);
|
||||
T.at<double>(1,0) = sin(new_prev_to_cur_transform[k].da);
|
||||
T.at<double>(1,1) = cos(new_prev_to_cur_transform[k].da);
|
||||
|
||||
T.at<double>(0,2) = new_prev_to_cur_transform[k].dx;
|
||||
T.at<double>(1,2) = new_prev_to_cur_transform[k].dy;
|
||||
|
||||
Mat cur2;
|
||||
|
||||
warpAffine(cur, cur2, T, cur.size());
|
||||
|
||||
cur2 = cur2(Range(vert_border, cur2.rows-vert_border), Range(HORIZONTAL_BORDER_CROP, cur2.cols-HORIZONTAL_BORDER_CROP));
|
||||
|
||||
// Resize cur2 back to cur size, for better side by side comparison
|
||||
resize(cur2, cur2, cur.size());
|
||||
|
||||
// Now draw the original and stablised side by side for coolness
|
||||
Mat canvas = Mat::zeros(cur.rows, cur.cols*2+10, cur.type());
|
||||
|
||||
cur.copyTo(canvas(Range::all(), Range(0, cur2.cols)));
|
||||
cur2.copyTo(canvas(Range::all(), Range(cur2.cols+10, cur2.cols*2+10)));
|
||||
|
||||
// If too big to fit on the screen, then scale it down by 2, hopefully it'll fit :)
|
||||
if(canvas.cols > 1920) {
|
||||
resize(canvas, canvas, Size(canvas.cols/2, canvas.rows/2));
|
||||
}
|
||||
|
||||
imshow("before and after", canvas);
|
||||
|
||||
//char str[256];
|
||||
//sprintf(str, "images/%08d.jpg", k);
|
||||
//imwrite(str, canvas);
|
||||
|
||||
waitKey(20);
|
||||
|
||||
k++;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
Loading…
Reference in a new issue